I may not have the exact answer to your question. But when I had a similar error related to zlib_.1.2.9 in another context, making LD_LIBRARY_PATH include path to the anaconda lib directory helped. Also to set that LD_LIBRARY_PATH, the Sys.setenv did not work. I did it from linux command line in the following way:
sudo /bin/bash -c "echo 'rsession-ld-library-path="pathname"' >> /etc/rstudio/rserver.conf"
sudo rstudio-server restart